“…The definition was modified to cod( χ) = |G : ker( χ)|/χ(1) by Qian et al in [18] so that there is no different meaning for cod( χ) when χ is considered as a character in some quotient group of G. Because the relationship between codegrees and degrees is very close, we may expect to characterise the structure of groups by codegrees. During the past few years, the study of character codegrees has been very active and many results have been obtained, including the relationship between codegrees and element orders, codegrees of p-groups and groups with few codegrees (see, for example, [2,8,11,14,15,17]).…”